In floor scrubbing machines of the type referred to above it is essential that the squeegee assembly properly track the brushes and conform to the surface of the floor in order to achieve satisfactory pickup of the cleaning fluid. For example, if the floor cleaning machine is to be turned it is necessary that the squeegee assembly swing independently of the machine in order to properly track the cleaned surface. Alternatively, if the machine is being advanced in a forward direction over a floor whose surface is not quite level, for example having high and low spots, it is necessary for the squeegee to conform to this surface. To this end, it is necessary that the squeegee assembly be able to tilt from side to side as well as to move up and down slight amounts in order to conform to the surface of the floor. In addition as the squeegees wear it is necessary that the squeegee assembly be able to move downwardly to keep the lower edge of the squeegees in contact with the floor surface. It is also necessary that the squeegee assembly be capable of upward movement to lift the squeegees from the floor as for example when transporting from a storage location to a working location, or when only scrubbing of the floor is desired.
Various designs for supporting the squeegee assembly have been proposed in the past, and one example is shown in copending U.S. application Ser. No. 186,420. Another design is shown in U.S. Pat. No. 4,339,841 issued July 20, 1982. While these designs have performed in a generally satisfactory manner it has been found that due to the crescent shape of the squeegee assembly utilized in these designs that it has been difficult to maintain the full length of the squeegee in contact with the floor surface with relatively instant down pressure under certain situations. For example, in both of the above designs relatively high forces are required to raise one side of the squeegee relative to the other, and it is desirable that the down force of the squeegee be maintained at a relatively constant level. In addition if both the forward wheels of the machine were to enter a low spot on the floor in the second of the two designs referred to above, the intermediate portion of the squeegee may actually lift off the surface of the floor to be cleaned. Other situations have been encountered where less than completely satisfactory performance has been achieved.